libplugin: mark the cmd notleak() whenever command_still_pending() called.

This is what we do in lightningd, which makes memleak much more forgiving:
you can hang temporaries off cmd without getting reports of leaks (also
when send_outreq called).

We remove all the notleak() calls in plugins which worked around this!
And avoid multiple notleak labels, since both send_outreq() and
command_still_pending() can be called multiple times.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

common/memleak.c

@@ -50,12 +50,16 @@ void *notleak_(void *ptr, bool plus_children)
 	name = tal_name(ptr);
 	if (!name)
 		name = "";
-	if (plus_children)
-		name = tal_fmt(tmpctx, "%s **NOTLEAK_IGNORE_CHILDREN**",
-			       name);
-	else
-		name = tal_fmt(tmpctx, "%s **NOTLEAK**", name);
-	tal_set_name(ptr, name);
+
+	/* Don't mark more than once! */
+	if (!strstr(name, "**NOTLEAK")) {
+		if (plus_children)
+			name = tal_fmt(tmpctx, "%s **NOTLEAK_IGNORE_CHILDREN**",
+				       name);
+		else
+			name = tal_fmt(tmpctx, "%s **NOTLEAK**", name);
+		tal_set_name(ptr, name);
+	}
 
 	return cast_const(void *, ptr);
 }

plugins/bcli.c

@@ -782,9 +782,6 @@ static struct command_result *sendrawtransaction(struct command *cmd,
 	} else
 		highfeesarg = NULL;
 
-	/* Keep memleak happy! */
-	tal_free(allowhighfees);
-
 	start_bitcoin_cli(NULL, cmd, process_sendrawtransaction, true,
 			  BITCOIND_HIGH_PRIO, NULL,
 			  "sendrawtransaction",

plugins/bkpr/bookkeeper.c

@@ -1294,7 +1294,7 @@ static struct command_result *lookup_invoice_desc(struct command *cmd,
 	struct out_req *req;
 
 	/* Otherwise will go away when event is cleaned up */
-	notleak(tal_steal(cmd, payment_hash));
+	tal_steal(cmd, payment_hash);
 	if (!amount_msat_zero(credit))
 		req = jsonrpc_request_start(cmd->plugin, cmd,
 					    "listinvoices",
@@ -1372,8 +1372,6 @@ listpeers_done(struct command *cmd, const char *buf,
 
 	if (info->ev->payment_id &&
 	    streq(info->ev->tag, mvt_tag_str(INVOICE))) {
-		/* Make memleak happy */
-		tal_steal(tmpctx, info);
 		return lookup_invoice_desc(cmd, info->ev->credit,
 					   info->ev->payment_id);
 	}
@@ -1591,8 +1589,6 @@ parse_and_log_chain_move(struct command *cmd,
 			if (tags[i] != INVOICE)
 				continue;
 
-			/* Keep memleak happy */
-			tal_steal(tmpctx, e);
 			return lookup_invoice_desc(cmd, e->credit,
 						   e->payment_id);
 		}
@@ -1673,8 +1669,6 @@ parse_and_log_channel_move(struct command *cmd,
 				maybe_record_rebalance(db, e);
 
 			db_commit_transaction(db);
-			/* Keep memleak happy */
-			tal_steal(tmpctx, e);
 			return lookup_invoice_desc(cmd, e->credit,
 						   e->payment_id);
 		}

plugins/commando.c

@@ -680,13 +680,12 @@ static struct command_result *json_commando(struct command *cmd,
 		tal_append_fmt(&json, ",\"rune\":\"%s\"", rune);
 	tal_append_fmt(&json, "}");
 
-	/* This is not a leak, but we don't keep a pointer. */
-	outgoing = notleak(tal(cmd, struct outgoing));
+	outgoing = tal(cmd, struct outgoing);
 	outgoing->peer = *peer;
 	outgoing->msg_off = 0;
 	/* 65000 per message gives sufficient headroom. */
 	jsonlen = tal_bytelen(json)-1;
-	outgoing->msgs = notleak(tal_arr(cmd, u8 *, (jsonlen + 64999) / 65000));
+	outgoing->msgs = tal_arr(cmd, u8 *, (jsonlen + 64999) / 65000);
 	for (size_t i = 0; i < tal_count(outgoing->msgs); i++) {
 		u8 *cmd_msg = tal_arr(outgoing, u8, 0);
 		bool terminal = (i == tal_count(outgoing->msgs) - 1);
@@ -705,12 +704,6 @@ static struct command_result *json_commando(struct command *cmd,
 		outgoing->msgs[i] = cmd_msg;
 	}
 
-	/* Keep memleak code happy! */
-	tal_free(peer);
-	tal_free(method);
-	tal_free(cparams);
-	tal_free(rune);
-
 	return send_more_cmd(cmd, NULL, NULL, outgoing);
 }
 

plugins/libplugin.c

@@ -297,6 +297,8 @@ struct command_result *command_finished(struct command *cmd,
 struct command_result *WARN_UNUSED_RESULT
 command_still_pending(struct command *cmd)
 {
+	if (cmd)
+		notleak_with_children(cmd);
 	return &pending;
 }
 
@@ -728,6 +730,8 @@ send_outreq(struct plugin *plugin, const struct out_req *req)
 
 	ld_rpc_send(plugin, req->js);
 
+	if (req->cmd != NULL)
+		notleak_with_children(req->cmd);
 	return &pending;
 }
 

plugins/pay.c

@@ -1202,10 +1202,6 @@ static struct command_result *json_pay(struct command *cmd,
 		}
 		payment_mod_exemptfee_get_data(p)->amount
 			= exemptfee ? *exemptfee : AMOUNT_MSAT(5000);
-
-		/* We free unneeded params now to keep memleak happy. */
-		tal_free(maxfee_pct_millionths);
-		tal_free(exemptfee);
 	}
 
 	shadow_route = payment_mod_shadowroute_get_data(p);

plugins/spender/fundchannel.c

@@ -108,9 +108,6 @@ json_fundchannel(struct command *cmd,
 	if (utxos)
 		json_add_tok(req->js, "utxos", utxos, buf);
 
-	/* Stop memleak from complaining */
-	tal_free(id);
-
 	return send_outreq(cmd->plugin, req);
 }
 

plugins/spender/multifundchannel.c

@@ -1832,8 +1832,8 @@ post_cleanup_redo_multifundchannel(struct multifundchannel_redo *redo)
 
 	/* Okay, we still have destinations to try: wait a second in case it
 	 * takes that long to disconnect from peer, then retry.  */
-	notleak(plugin_timer(mfc->cmd->plugin, time_from_sec(1),
-			     perform_multifundchannel, mfc));
+	plugin_timer(mfc->cmd->plugin, time_from_sec(1),
+		     perform_multifundchannel, mfc);
 	return command_still_pending(mfc->cmd);
 }
 
@@ -2064,9 +2064,6 @@ json_multifundchannel(struct command *cmd,
 
 	mfc->sigs_collected = false;
 
-	/* Stop memleak from complaining */
-	tal_free(minconf);
-
 	perform_multifundchannel(mfc);
 	return command_still_pending(mfc->cmd);
 }